| Abstract [eng] |
One of the most important characteristics considering application of the laser beam is its transverse beam profile. Most widely used profile is a Gaussian beam. However, in some applications Bessel-Gauss beam can be more beneficial due to its long Rayleigh zone. For example, in fabrication of transparent materials one can modify larger volume with a single pulse using Bessel beam instead of a Gauss beam. To achieve a more homogeneous on axis modification an ability to control axial beam intensity profile is required. In this work I present a method for generation of a quasi-Bessel vortex beam which in contrary to a Bessel vortex beam has an arbitrary intensity distribution. I analyze influence of topological charge and beam length to transverse intensity distribution. Next, I introduce a spatial array of independent quasi-Bessel vortices and report on physical limitations for a formation of this array due to mutual interference of individual beams. Main results show that increase in topological charge or beam length leads to a more pronounced interference pattern and longer distances between individual beams are needed to distinguish these beams. Finally, I show, that by choosing right parameters it is possible to minimize effects due to the harmful interference and form various spatial structures from parallel displaced quasi-Bessel vortex beams. |
